1. Field of the Invention
The present invention relates to a trocar system for inserting and retaining a trocar for use as a guide tube of an insertion instrument into a body cavity into a patient's body wall.
2. Description of the Related Art
In a trocar system, for example, a probe including a sharp puncturing needle on a tip end, and a trocar which is disposed in an outer periphery of the probe and which is to be inserted and retained in a patient are detachably combined. The trocar system is stuck into the patient's body wall and guided into a body cavity in a state in which the probe and trocar are integrally combined. When the probe is detached from the trocar in this state, only the trocar is retained in the body wall. This trocar is used as a guide tube in a scope for observing various lesioned parts and a treatment instrument for performing a treatment.
Various modes of the trocar system have heretofore been known. For example, in Jpn. Pat. Appln. KOKOKU Publication No. 5-57863, an ultrasonic trocar system has been disclosed. For the ultrasonic trocar system, the probe is ultrasonically vibrated in the state in which the probe is integrally combined with the trocar, and a punctured hole can be formed in the patient's body wall. As a result, the probe can safely be stuck and guided into the body wall with a comparatively light force by the ultrasonic vibration. The trocar can also be guided into the body wall following the probe. The probe is detached from the trocar, and the trocar is retained in the body wall.
In Jpn. Pat. Appln. KOKAI Publication No. 2002-177293, an improved ultrasonic trocar system has been disclosed. For this ultrasonic trocar system, a dilator whose tip end is formed to be tapered substantially in a conical shape is disposed between the trocar and the probe whose outer diameter is comparatively small. In this system, the tapered tip end of the dilator projects from the tip end of the trocar. The tip end of the probe projects from the tapered tip end of the dilator. In the ultrasonic trocar system in this state, the probe is ultrasonically vibrated and guided into the patient's body wall. Thereafter, an operator holds the dilator and trocar, and dilates a cavity in the patient's body wall with the trocar. Then, the trocar system is guided into the body wall. Thereafter, the probe and dilator are removed from the trocar to retain the trocar in the body wall.